/*input
2 2
1 2
1
2
*/
#include<bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<long long,null_type,less_equal<long long>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
#pragma GCC optimize("Ofast")
//#pragma GCC target("avx2")
//order_of_key #of elements less than x
// find_by_order kth element
using ll=long long;
using ld=long double;
using pii=pair<ll,ll>;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()),c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
const ll maxn=5e5+5;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
const int INF=0x3f3f3f3f;
const ll MOD=998244353;
const ld PI=acos(-1.0L);
const ld eps=1e-6;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
out<<P.f<<' '<<P.s;
return out;
}
template<typename T>
ostream& operator<<(ostream& out,vector<T> V){
REP(i,sz(V)) out<<V[i]+1<<((i!=sz(V)-1)?" ":"\n");
return out;
}
ll mult(ll a,ll b){
return a*b%MOD;
}
ll mult(ll a,ll b,ll mod){
ll res=0;
while(b){
if(b&1) res=(res+a)%mod;
a=(a+a)%mod;
b>>=1;
}
return res;
}
ll mypow(ll a,ll b,ll mod){
if(b<=0) return 1;
a%=mod;
ll res=1LL;
while(b){
if(b&1) res=(res*a)%mod;
a=(a*a)%mod;
b>>=1;
}
return res;
}
int par[maxn],dep[maxn];
vector<int> v[maxn],comp[maxn];
struct UFDS{
int par[maxn];
void init(int n){
REP(i,n) par[i]=i;
}
void merge(int a,int b){
a=find(a),b=find(b);
if(a==b) return;
par[a]=b;
}
int find(int u){
if(par[u]==u) return u;
return par[u]=find(par[u]);
}
}uf;
void dfs(int u,int p){
par[u]=p;
for(int x:v[u]){
if(x==p) continue;
dep[x]=dep[u]+1;
dfs(x,u);
}
}
void merge(int a,int b){
a=uf.find(a),b=uf.find(b);
while(a!=b){
if(dep[a]>=dep[b]){
uf.merge(a,par[a]);
a=uf.find(a);
}
else{
uf.merge(b,par[b]);
b=uf.find(b);
}
}
}
int cnt[maxn];
int32_t main(){
ios::sync_with_stdio(false),cin.tie(0);
int n,k;
cin>>n>>k;
REP(i,n-1){
int a,b;
cin>>a>>b;
--a,--b;
v[a].pb(b),v[b].pb(a);
}
dfs(0,-1);
REP(i,n){
int x;
cin>>x;
--x;
comp[x].pb(i);
}
uf.init(n);
REP(i,n){
for(int x:comp[i]){
merge(x,comp[i][0]);
}
}
REP(i,n){
for(int x:v[i]){
if(uf.find(i)!=uf.find(x)){
cnt[uf.find(i)]++,cnt[uf.find(x)]++;
}
}
}
int ans=0;
REP(i,n) if(uf.find(i)==i and cnt[i]==2) ++ans;
cout<<(ans+1)/2;
}
